But in his day, the German composer was held responsible for a lot more than fainting and heart palpitations: his works were viewed as a threat not only to the health of musicians and listeners but also to any society that was trying to uphold order.

"No musician's music was seen as such a potentially dangerous stimulant as Wagner's," says James Kennaway, a historian specialising in music and medicine. "While the Nazis famously saw him as a model of musical health, at no time before or since the 1800s has one figure so dominated the debate on music as a pathogen as Wagner."

His music was seen not just as a symptom of the physical and sexual pathologies associated with a nervous modernity – everything from neurasthenia [nervous exhaustion] and degeneration to perversion and fatigue – but also as the direct cause of these.

Respected doctors blamed him for much mental illness, with the Dutch psychiatrist Jacob van Deventer concluding in 1891 that "a large number of the mentally ill are passionate lovers of Wagnerian music".

The medical profession put this down partly to the sheer length of his operas, partly to the "pathological lack of rhythm" in Wagner's music, which led the late-19th-century author of popular science Grant Allen to conclude that the "gathered energy has to dissipate itself by other channels, which involves a certain amount of conflict and waste, leading to fatigue". This was also a time when the medical profession widely believed that disease was "unrhythmical" while health was "rhythmical".

Probably the first acknowledged victim of the nervous strain caused by what Kennaway calls Wagner's "lush timbres and radical harmonies" was Ludwig Schnorr von Carolsfeld, the first singer of Tristan und Isolde, who died in 1865 in a "Tristan" delirium at the age of 29 shortly after his debut performance, muttering: "Farewell, Siegfried; console my Richard!" In a letter, a distraught Wagner admitted his music had "driven the singer to the abyss".

Women were considered to be particularly susceptible to the "disease" of musical nervousness that was often referred to as Wagnerianism. The music was inextricably linked to eroticism (take the incest in Die Walküre and the adultery in Tristan), and was believed to nurture dangerous sexual feelings among young, unmarried women. Wagner was blamed not only for the premature onset of menstruation but also infertility, melancholy, hysteria and hypnosis.

Just as men of a nervous disposition were encouraged to stay away from whisky, love affairs and cigars, so women were urged to avoid piano-tuning and Wagner.

In one recorded case, a psychiatric patient was said to have been haunted by Wagnerian auditory hallucinations, while Wagner's very own patron, King Ludwig II of Bavaria, passed out during a performance of Tristan because of nervous strain. Aloys Ander, who played Tristan in a Vienna production, died insane in an asylum in 1865.

"The idea of music being a potentially unhealthy form of stimulation, similar to drugs or electricity, had been commonplace during the 19th century," says Kennaway. "But with Wagner, the danger became specifically associated with modern music and modern urban lifestyles in diagnosing the fashionable disease of the time, neurasthenia."

Critics even suggested that Wagner's music was sickly and feminine, a suspicion that prompted a popular link to be made between Wagner and homosexuality – viewed then as a medical condition – which was said to be connected to the erotic power of music.

Wagner himself was seen as effeminate – he was very partial to silks and satins, which he ordered in huge quantities from Paris – in marked contrast to the macho image of him that the Nazis projected, which survives to this day.

Kennaway attributes the widespread and well-documented illnesses attached to Wagner's music in part to the fact that people rarely had the opportunity to listen to live performances.

"Even if you were living in a city, you'd be lucky to see Tristan and Isolde even three times in your lifetime, so the impact of it on many may well have been overwhelming," he says.

Added to which, Wagner made early use of such innovative techniques as stage curtains, smoke and steam machines, and the dimming of lights in his theatres – a new practice that in itself led to the rise of a new craze of "theatre groping".

The other novelties he employed in his Bayreuth theatre included hiding the orchestra in a pit – which was said to increase the music's potency – and first-class acoustics. These were interpreted as devices, says Kennaway, to "bypass the conscious mind and influence the audience via the nerves".

It was, in fact, Friedrich Nietzsche, one of Wagner's erstwhile most passionate friends and supporters, who delivered the most damning verdict on the medical dangers posed by his fellow German: in his 1888 book The Case of Wagner, he unleashed a diatribe, asking: "Is Wagner actually a man? Is he not rather a disease?"

• This article was amended on 22 May 2013. The original said Ludwig Schnorr von Carolsfeld died in 1859. This has been corrected to say 1865. It was further amended on 23 May 2013 to correct Schnorr's deathbed quote. The original had it as: "Farewell, Siegfried; console me, Richard!"